The major goal of this project is to understand the biochemical events involved in the response of individual cells to external signals. We have previously shown that several types of hormone/neurotransmitter receptors increase in several cell lines when the cells are grown in the presence of certain short chain fatty acids. For example, in HeLa cells beta-adrenergic receptors increase about four-fold in the presence of butyrate which permitted us to analyze the biochemical events in adenylate cyclase activation by hormones and describe a role for phospholipid methylation in receptor function. During this reporting period, we have shown that a pituitary tumor cell line also contains inducible beta-adrenergic receptors and may contain alpha-adrenergic receptors as well. We have continued to explore the mechanisms by which butyrate induces biochemicaL differentiation; butyrate does not affect the proteins associated with polysomal RNA but does reduce mRNA methylation which may influence translation of these molecules. Studies on benzodiazepine receptors in cultures neurons have continued and the value of this receptor as a neuron-specific marker has been shown.